A word-processor or personal computer has a good function to input, edit, print, and save quite freely "a sentence with Chinese character and Japanese syllabary" and various letter, symbol, drawing, and so on, will being necessary a tool (writing utensils) in future.
However, writing utensils are inconvenient for being to big and heavy and it is not easy to carry. It still has inconveniences that it cannot be put in a pocket, be handled by one hand, and is bard to be operated.
Because it is for reason of the mechanism in a word-processor or personal computer, further a surface of keyboard, and a unavoidable limitation of miniaturization for crowding with keys over eighty even of a portable type.
Namely, because it is miniaturized without decreasing the figure of 80 keys, the keys are close in formation and it is hard to type. Conversely, if the figure of keys are decreased simply, a crucial function is deteriorated and it is meaningless.
Is there any way to input more rapidly like a pocket calculator without damaging original performances of a word-processor or a personal computer? If it is possible, anybody can go for a work and a play with it in a pocket and a new media world which is completely different from now will be able to be opened.
Therefore, the development of keyboard has been required for a long time that the keyboard of the wordprocessor and personal computer could be minimizing as "a pocket calculator" in addition to easy typing in both of Japanese and English and all operation on the keyboard could be operated by one hand. Following five needed conditions are necessitated to meet the demand that figure of keys on the keyboard are drastically reduced with ensuring ability more than conventional keyboard.
1. "miniature" size to be able to type with holding by a hand. PA0 2. "brevity" to input letter and symbol. PA0 3. "simplicity" to make a selection from abundant functions. PA0 4. "simplicity" to change respective modes. PA0 5. "a high speed" to input with Japanese and English. PA0 1. The letter arrangement has such rules as much as possible that it is easy to remember. PA0 2. The high frequent letters are arranged at easy pressing key positions. PA0 3. The position of the high active finger, such as an index or thumb should be wide and the used frequency should be high. PA0 4. The activity becomes lower in the order of a middle, ring and little fingers, so that the used frequency needs to be adjusted to the order.